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javaawtkeylistenerkeyevent

How to restrict KeyEvent capture speed

I'm making a fairly basic top down 2D shooting game (think Space Invaders) but I'm having an issue with KeyEvent processing too many events per second.

I have this:

if (e.getKeyCode() == KeyEvent.VK_SPACE){
    shoot();
}

shoot() creates a bullet and sets it firing upward, but a problem arises if you simply hold down space to fire hundreds of bullets, making the game trivial.

Is there a way to make it process only one or two keypresses per second, ignoring the rest?

Solution

  • You could use a handmade timer so that it will be either lightweight either easily customizable, something like:

    long lastShoot = System.currentTimeMillis();
final long threshold = 500; // 500msec = half second

public void keyPressed(KeyEvent e) { 
  if (e.getKeyCode() == KeyEvent.VK_SPACE)
  {
     long now = System.currentTimeMillis();
     if (now - lastShoot > threshold)
     {
       shoot();
       lastShoot = now;
     }
  }
}